Process for clarifying and improving the color of hydrocarbon oils



Javn. 29, 1935.

PROCESS FOR CLARIFYING AND IMPROVING THE COLOR 0F HYDROCARBON OILS 'Filed Feb. 21, 1927 Patented Jan. 29,- 1935 UNITED STATI-:s

rRocEss Fort cLAaIFYmG AND nurnov nvGTnE coton or mmnocARBoN oILs Merle M. Moore, Robert R. Thorbum, and William B. Wilson, El Segundo, Calif., assgnors, by mesne assignments, to Contact Filtration Company, San Francisco, Calif., a

of Delaware corporation Application February 21, 192,7, yseien No. 169,789

12 claims. (c1. 19e- 147) This invention relates to the art of clarifying and improving the color of hydrocarbon oils by the use of clarifying and decolorizing agents, and can be adapted forthe treatment of all types of oil, but the same is more particularly adapted for use in connection with petroleumdubricating oils.

An object of the invention is to simplify and expedite the decolorizing and purification of the oils with any comminuted solid adsorbent such; for example, as minerals ofthe montmorillonite type, Florida fullers earth, minerals of the'serpentine group and like material which may or may not have been givenvan acid or other treatment for the production of the decolorizing agent.

One object of the invention is to provide a method or process whereby a substantially uniform claried oil of the desired color may be produced with a minimum consumption of the clarifying and decolorizing agent; another object is to provide such a process which may be performed with a minimum consumption of time if desired.

An object of the invention is to provide a method wherebyhydrocarbon oil may be mixed vlwith a clarifying and decolorizing agent and heated to. a temperature of 230 F., or higher, thoroughly commingled so that no substantial oxidation can take place during the treatment.

An object of' the invention is to provide a method whereby a finely comminuted decolorizing and clarifying agent may be used to clarify and decolorize a hydrocarbon oil with the exclusion of substantially all air therefrom.

An object of the invention is to provide a, method or process whereby it is not necessary to for a given quantity and weight, the ner the comminution of the decolorizing agent, the more surface thereof will be exposed to the oil and the more coloring matter will be condensed or adsorbed upon the surface of the decolorizing agent. It is now generally well known that a decolorizing agent, ground to approximately 200 mesh gives satisfactory results for the hot contact method, and reference is hereby made to the United States Patents Nos. 1,404,374 and 1,404,375.

This process in general is an improvement upon the United States Patents Nos. 1,404,374 and 1,404,375, in that the operation is conducted in a substantial vacuum or reduced pressure less than atmospheric so that no substantial amount of air will be commingled with the oil at any stage of treatment.

By well known methods it has been customary in treatment of oils with a mineral adsorbent solid for the decolorization and purification to take place quickly before any substantial oxidation may take place, to treat an oil containing water, or to introduce water into the oil to be treated which during the treatment is converted into steam and by` excluding most .of the air from quently cause regurgitation with consequent lossV due to rehandling. By our method these diiculties are overcome. and the treatment may be performed in any period of time that is desired.

`We have further discovered that the employment` of steam or water in the oil to be treated for the purpose of generating a'steam to exclude the air during the operation is also somewhat detrimental to the emciency of the operation, in-

sofar as a small amount of moisture may sur-.

round the particles of the agentand thus prevent to a certain extent the intimate contact between the oil and the agent. By our process this is entirely yavoided since a dry oiland a substantially dry agent may be employed.

In the preferred embodiment of our invention, our method or process in clarifying and improv- `ing the color of hydrocarbon oils, consists either j in batch treatments or by continuous methods whereby hydrocarbon oils or lubricating oils are slowly or quickly heated to 230 F., or higher, by suitable heating devices while such. oil is commingled with a. suitable clarifying and decolorizing agent-in a finely comminuted orpulver'ized condition and in such quantities as is necessary to obtain the desired color and grade; vcontinuing the commingling vor agitating of such hydrocarbon oil and decolorizing agents in the absence of any substantial amount of air for such a period of time and at such a temperature as is necessary to obtain the desired extraction of colorl from the oil; and separating therefrom the decolorizing agent and adsorbed coloring matter by any suitable means; and finally cooling said decolorized oil in the absence of air to the desired temperature where no substantial oxidation will take place. It is, however, not necessary that certain types of oil be cooled before exposure to the atmosphere following separation of the oil from the used decolorizing agent.

More specically our invention provides a process whereby hydrocarbon oil without the presence of any substantial amount of air may be either heated quickly or slowly to the desired temperature (substantially above 230 F.) by circulating through heated pipe coils or tubes or in any suitable vessel or chamber, without any substantial part of said oil being heated beyond the desired temperature; thoroughly commingling the heated oil and decolorizing agent in the absence of any substantial amount of air; separating the adsorbed decolorizing and clarifying agent and coloring matter from'the oil.-

I n addition to the clarifying and decolorizing agents named herein it is to be understood that these agents or any other agents may be used in an acidied state; for example, the agent may be any clay or earthy material, treated or'untreated, to which approximately 1 to 10% of concentrated Y sulphuric acid has been added.

Also it is to be understood that the oil to be treated may be a mineral lubricating oil stock i vwhich has been treated with` sulphuric acid and 'has not been subjected to the caustic soda neutralizing operation, in which case a neutral oil may be obtained after the decolorizing operation, the acid bodies in the oil being decomposed with the elmination of sulphur dioxide by thevacuum `which is maintained on the treater.

The preferred embodiment of our invention will be more readily -understood by reference to the accompanying drawing, illustrating a form of apparatus by which the same may be performed. The drawing is a diagrammatical form of an apparatus by which such preferred embodiment of our invention may be carried out.

In the drawing, 2 represents a storage tank for the oil to be treated. The tank 2 is connected l by a pipe 3'with a treating tank 4 and controlled by a valve 40. The tank 4 is connected with a pipe 6 leading to an exhauster 42 controlled by a vacuum valve 43. The pipe 6 is also provided with a valve 41 which may also be used to regulate the vacuum upon treating tank 4. The treating tank 4 is connected by means of a pipe 7 to a pump 8 controlled by a valve 5 which discharges .through a pipe 9 connected through a valve 10 to a heater 11, and through a pipe 12 back to the treater 4 controlled by a valve 44.

'Ine heater 11 may be of any suitame ferm or' construction such as a Braun heater, which is a heater composed of small pipes enclosed in a shell so that the heating medium lls the shell and surrounds the pipes through which the oil is conducted, thus affording a quick means, if desired, of raisingthe temperature of the oil as ity passes through the pipe or tubes of the heater.

.The pipe 7 is provided with a branch pipe 45 controlled by a valve 46 and connected to pipe* ceiving tank 13, a pipe 15 controlled by a valve 16 leads to a lter press or other means, not shown, of separating the spent clarifying and decolorizing agent from the treated oil. From pipe 6, a branch line 17 controlled bp a valve 18 leads to the top of receiving tank 13 for the purpose of maintaining a .vacuum on this tank. 19 represents a storage and feeder bin or hopper in which nely comminuted clarifying and decolorizing agent is provided. From'this bin 19 such agent may be introduced into .the treating tank 4 in the desired quantities, such quantity being regulated by means of a suitable regulator or valve 20.-

Treating or mixing tank-4 is provided with a mechanical stirrer 21 which may be operated by belt power. The heater 11 is connected to a pipe 22 leading to and connecting with receiver 13 controlled by a valve 23, by means of which the oil may be discharged directly through the heater and into the receiving tank 13, so as to permit of continuous operation if desired.

When the apparatus is in the form shown in the drawing, the preferred embodiment of our process is performed by batch operation as follows:

The treating tank 4 is mst fined with apredetermined amount of hydrocarbon oil to be treated. Such hydrocarbon oil is' generally a.

lubricating fraction of mineral oil, such as petroleum oil, reduced to the desired viscosity. Such oil is also one which has been previously treated with sulfuric acid, usually less than 10% by weight of the oil. The lubricating oil may be, prior to the decolorizing treatment, neutralized by a neutralizing agent such as caustic soda, although in one form of the process the oil is left in the acidic state containing small percentages of sulpho-acids and reliance placed upon the decolorizing process for also serving the function of neutralizing the lubricating oil stock. 'I'he lubricating oil stock employed may vary widely in viscosity and gravity. For example, lubricating stocks having a viscosity of 60-2000 seconds Saybolt at 100 F. may be employed, and lubricating oils having a gravity of from 18 to 29 Baum may be employed.

Such oil is drawn through pipe 3 from the storage tank 2 and passed into the mixing tank 4. Therein a decolorizing and clarifying agent in the required amount is admitted by operation of the valve 20. The decolorizing agent will be employed in quantities depending upon the color of the lubricating oil to beldecolorized and the desired flnal color.` Generally there is employed one ton of the decolorizingfagent to each 500 to 25,000 gallons of lubricating oil to b e treated.

Within the mixing tank 4, the decolorizing agent is thoroughly cmmingled with the oil by means of the mechanical agitator 21 and at the same time the oil is circulated through pipe '7,

pipe 9, through heater 11, and back to the treating tank 4 through pipe 12. This circulation is continued until the oil has attained the reaction temperature suitable for the extraction of the coloring matter by the agent. Preferably the reaction temperature is above 240 F., and most desirably at approximately 450 F. In certain cases where lubricating stock of very high viscosity is treated, a temperature of greater than 450 F. may beremployed.

It is understood that prior to the elevation of the admixed lubricating oil stock and decolorizing agent to the reaction temperature, the apparatus is placed under a pressure sulciently less than `atmospheric as to extract from the admixture Lacasse substantially all the oxygen or air to inhibit said air or oxygen operating to oxidize the oil during the decolorizing treatment. Usually the vacuum employed is less than that corresponding to an absolute pressure of one inch of mercury.

The circulation of the admixture through the heater is continued until the oil 'and decolorizing agent have been subjected to the reaction temperature for lthat period of time necessary to substantially complete the clarifying and decolorizing action upon the petroleum oil. Where the oil employed is one having other than sulphoacids or is an oil which has been treated with sulfuric acid without neutralization, the time of contact is continued until all of the acid reaction products and-sulpho-acids are decomposed and the excess for said treatment drawn off' by the vacuum pumpor exhauster 42. After the corri-- mingled oil and agent have been raised to the desired temperature and subjected to this'temperature for the necessary period of time to clarify and decolorize the oil, the oil passes through the bottom of the mixing tank 4 and through pipe 7 into the suction side of pump 8, through line 9,

- andv into the receiving tank 13, valves 5 and 14 being open and valves 46 and 10 being closed.

The hydrocarbon oil and the spent clarifying and decolorizing agent in receiving tank 13 is then conducted through a line 15 controlled by a valve 16 to a filter press, not shown, where the said agent and its adsorbed coloring matter is separated from thev purified oil and discharged to a storage, not shown.

While as heretofore stated, any clarifying and decolorizing agent may be used, we prefer to use acid treated clays of the montmorillonite type, such as occur in well known deposits in Nevada and in California and known as Death Valley clay or San Diego clay; also certain other earthy materials may'be used, such as a magnesium silicate of the serpentine group. 'v

The period of time required for clarifying and decolorizing the hydrocarbon oil with a decolorizing agent depends upon the material employed, the oil tobe decolorized and the temperature, which with certainroils does n ot exceed l hour, althoughthe period of time taken to decolorize the oil does not materially affect the final results since the air is excluded-and no oxidation can be After the agent has been separated from the purified oil and delivered into the receiving tank,

It is known cooling. A

While we preferto use a filter press as a means of separating the clarifying and decolorizing agent from the oil, our process is not necessarily limited thereto as we, may use any suitable means, centrifugal machines or, other mechanical devices known in the art. l

We claim:

1. The process of clarifying and improving the color of hydrocarbon oils while in the liquid state which consists in commingling with the oil to be treated a comminuted solidadsorbent in a closed treating tank, under pressure below atmospheric sufficient to extract and eliminate substantially all the air and vapors other than the vapors of' the oil being treated therefrom, heating the -mixture to a temperature above 230 F. and vbelow the boiling ypoint ofthe oil at such sub-atmospheric pressure so that the coloring matter willvcolor, and-producing a hydrocarbon lubricating be adsorbed b y the said. comminuted solid ad.-l

sorbent, and nally separating the spent adsorbent and its contained coloring matter from the decolorized oil. y

2. The process of clarifying and improving the color of hydrocarbon oils while in the liquid state which consists in commingling with the oil to be treated a comminutedsolid decolorizing agent in a closed treating tank under a pressure below atmospheric sufficient to extract and eliminate substantially all the air and vapors other than the vapors of the oil being treatedtherefrom, heating under an absolute pressure less than atmospheric, and sufficient to reduce the air and vapor content and below the boiling point of oil at such sub-atmospheric pressure so that' no substantial oxidation of the hydrocarbon oil can take place therein, and finally separating the spent adsorbent and its contained coloring matter from the decolorized oil.

t 3. The process of clarifying and improving the color of hydrocarbon oils while in the liquid state which consists in commingling with the oil to be treated a comminuted solid adsorbent in a closed treating tank under a pressure below atmospheric sucient to extract and eliminate substantially all the air and vapors therefrom, maintaining the mixture in a commingled state at a temperature above 230 F., 'and at a temperature sufficient to eliminate all the air and vapors other than the vapors of the oil being treated therefrom and below a temperature at which the oil being treated boils at such sub-atmospheric pressure containing small percentages of sulpho acids,

which consists in commingling with the oil to be treated a comminuted solid .adsorbent in a closed treating vessel under a pressure below atmospheric suicient to extract and eliminate substantially all the gases and vapors therefrom other than vapors of the oil being treated, heating the mixture to such a temperature that 'the coloring matter will be adsorbed by said comminuted solid adsorbent material and below boiling point of the oil at such sub-atmospheric pressure, and at the same time to decompose the sulpho acids contained therein, continuously removing all gases and vapors produced thereby, andnally separating the spent adsorbent and its contained coloring matter from the decolorized oil.

5. The process of clarifying, improving the color I and producinga neutral hydrocarbon oil from an acid treated oil, which consists in commingling with the liquid oil to be treated a comminuted solid adsorbent, in a closed treating vessel under a pressure below atmospheric sufficient to extract and eliminate substantially all the gases and vapors other than vapors of the' oil being treated therefrom, heating the* mixture to such a temperature that the coloring matter will be adsorbed and the sulpho acids decomposed while maintaining the oil in the liquid state, without distilling the oil being treated during said absorption reaction continuously removing all gases and fvapors produced thereby, and finally separating the spent adsorbent and its contained coloring matter from the decolorized oil.

6. The process of clarifying, improving the oil, substantially free of mineral acid acidity, fromA oil is maintained in the liquid state, without distilling the oil being treated during said absorption reaction, continuously removing all gases and vapors produced thereby, and nally separating the spent adsorbent and its contained coloring matter from the decolorized oil.

7. The process of clarifying, improving the color, and producing a lubricating oil substantially free of mineral acid, acidity, from a lubricating oil stock which contains small percentages of sulphuric acid and sulpho acids, which consists in commingling with the liquid oil to be treated acomminuted solid adsorbent, in a closed treating vessel under a reduced pressure less than 4 inches of mercury to extract and eliminate substantially all the air, sulphur dioxide, and vapors therefrom, heating the mixture to a temperature above 230 F. while maintaining the oil in the liquid state, continuously removing all gases and vapors produced thereby, and nally separating the spent adsorbent and its contained coloring matter from 'the decolorized oil.

8. A process of clarifying and improving the color of hydrocarbon oils in a liquid state which consists Vin 'commingling with the oil to be treated a comminuted solid absorbent in a closed treating tank `nder an 'absolute pressure of less than four inches of mercury, heating the mixture to a temperature so that th`e coloring matter Will be absorbed by said comminuted solid adsorbent,

maintaining said vacuum therein, and nall'y separatingthe spent adsorbent and its contained coloring matter from the decolorized oil While the oil is maintained in liquid state.

49. A process of purifying and partially decolorizing hydrocarbon oil in the liquid state by heating such oil in intimate contact with a nely divided decolorizing agent at a temperature above 230 Fahrenheit, at a reduced pressure suillcient- 1y less than atmospheric to substantially prevent oxidation, and then separating oil from the used decolorizing agent while maintaining the oil in liquid state.

10. A method of refining oils, comprising subjectinga mixture of liquid oil and a solid adsorbent material in' a reaction zone to sub-atmospheric pressure and a temperature below 250 F., to remove air and moisture contained in said mixture, discharging water vapors from said reaction zone during such treatment, increasing the temperature of said mixture to above 250 F., while maintaining such mixture in a liquid state, said temperature and vacuum being insuftcient to vaporize a substantial vportion of the oil, dis-A charging from said zone and separately condens ing any vaporized portions of the oil, and nally discharging the treated oil and adsorbent from said zone and separating the oil from the adsorbent.

11. A method of refining oils, comprising subjectng' a mixture of liquid oil and solid adsorbent material in a reaction zone to sub-atmospheric pressure and a temperature below that ing the treated liquid oil and adsorbent from said i zone and separating the oil from the adsorbent.

12. A method of refining oils, comprising subjecting a .mixture of `liquid oil and a solid adsorbent material in a reaction zone to a sub-atmospheric pressure and a temperature below that at which substantial reaction occurs between the oil and adsorbent, so as to remove air and moisture contained in said liquid mixture, circulating the mixture into-and out of said zone during such treatment, discharging evolved water vapors from said reaction zone during such treatment, increasing the-temperature of said liquid mixture to a reaction temperature, to cause said adsorbent to aiect the oil, said temperature and vacuum being insufficient to vaporize a substantial portion of the oil, removing from'said zone and condensing any portion of the oil vaporized during such further treatment, and nally discharging.. the treated liquid oil and adsorbent from said zone, and separating the oil from the adsorbent.

MERLE M. MOORE. -ROBERT R. THORBURN. WILLIAM B. WILSON. 

